Testosterone and reproductive effort in male primates

Abstract

Considerable evidence suggests that the steroid hormone testosterone mediates major life-history trade-offs in vertebrates, promoting mating effort at the expense of parenting effort or survival. Observations from a range of wild primates support the “Challenge Hypothesis,” which posits that variation in male testosterone is more closely associated with aggressive mating competition than with reproductive physiology. In both seasonally and non-seasonally breeding species, males increase testosterone production primarily when competing for fecund females. In species where males compete to maintain long-term access to females, testosterone increases when males are threatened with losing access to females, rather than during mating periods. And when male status is linked to mating success, and dependent on aggression, high-ranking males normally maintain higher testosterone levels than subordinates, particularly when dominance hierarchies are unstable. Trade-offs between parenting effort and mating effort appear to be weak in most primates, because direct investment in the form of infant transport and provisioning is rare. Instead, infant protection is the primary form of paternal investment in the order. Testosterone does not inhibit this form of investment, which relies on male aggression. Testosterone has a wide range of effects in primates that plausibly function to support male competitive behavior. These include psychological effects related to dominance striving, analgesic effects, and effects on the development and maintenance of the armaments and adornments that males employ in mating competition.

Mothers' and fathers' joint profiles for testosterone and oxytocin in a small‐scale fishing‐farming community: Variation based on marital conflict and paternal contributions

“…Men's provisioning roles also represent social mechanisms through which they acquire status in the community (Boyette et al, ). Thus, these represent potential psychobiological pathways linking elevated T and provisioning among Bondongo fathers, as risk taking behavior and competition for status are both social–behavioral domains that have been linked to elevated T in humans and other primates (Boyette et al, ; Gray, Reece, et al, ; Muller, ). For fathers' OT, past observational research on Israeli families showed that men with elevated OT were more affectionately and positively engaged when they interacted with their infants (Feldman et al, , ; Gordon et al, ).…”

Looking for unity in diversity: human cooperative childcare in comparative perspective

“…For instance, these trade-offs may bias against helping in species with yearround nesting but not in seasonal species [98]. In the latter, individuals who did not manage to breed will anyway have to wait until the next year to mate, and therefore the reduced testosterone levels associated with helping [96,99] will not compromise mating success in the following year.…”

Phytosteroids beyond estrogens: Regulators of reproductive and endocrine function in natural products

“…In males, testosterone is required for reproductive processes such as sexual behavior and sperm production (Borst and Yarrow, 2015; Muller, 2016). Outside the reproductive system, testosterone has important actions such as maintaining muscle mass and bone density of men (Borst and Yarrow, 2015; Sinnesael et al, 2011).…”